U.S. patent application number 10/790384 was filed with the patent office on 2005-09-01 for liquid level sensor with odor reduction for waste holding tanks.
Invention is credited to Stewart, Glen Harris.
Application Number | 20050189275 10/790384 |
Document ID | / |
Family ID | 34887463 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050189275 |
Kind Code |
A1 |
Stewart, Glen Harris |
September 1, 2005 |
Liquid level sensor with odor reduction for waste holding tanks
Abstract
A sensor for determining liquid level while reducing odor for
use in a marine vessel or RV waste holding tank. The sensor
includes an aeration tube and a pressure sensor. The aeration tube
is disposed in a bottom portion of the holding tank. An aeration
pump is in fluid communication with the aeration tube and the
pressure sensor and supplies pressurized air to the aeration tube.
The aeration tube is disposed in a bottom-most portion of the
holding tank and is submerged in sewage. The pressure in the
aeration tube is measured by the pressure sensor and the pressure
is correlated to liquid level in the waste holding tank.
Pressurized air from the aeration pump is injected into the sewage
via the aeration tube and creates an oxygen-enriched aerobic
environment therein. Air from the holding tank is continuously
vented to atmosphere via a vent in the tank.
Inventors: |
Stewart, Glen Harris;
(Ellicott City, MD) |
Correspondence
Address: |
Mr. Glen Stewart
P.O. Box 123
Glenelg
MD
21737-0123
US
|
Family ID: |
34887463 |
Appl. No.: |
10/790384 |
Filed: |
March 1, 2004 |
Current U.S.
Class: |
210/86 ; 210/220;
210/90; 73/299; 73/866.5 |
Current CPC
Class: |
C02F 2209/42 20130101;
C02F 2209/03 20130101; Y02W 10/15 20150501; C02F 2103/008 20130101;
C02F 2303/02 20130101; C02F 3/02 20130101; B63B 29/16 20130101;
C02F 1/008 20130101; Y02W 10/10 20150501 |
Class at
Publication: |
210/086 ;
210/220; 210/090; 073/299; 073/866.5 |
International
Class: |
C02F 001/74 |
Claims
What is claimed is:
1. A sensor for use in detecting the level of liquid in a waste
holding tank, comprising: a pressure sensor, an aeration tube, and
a supply of air, said pressure sensor being disposed on the
aeration tube; said aeration tube being disposed in a holding tank,
with one end outside the tank and connected to an air supply tube
connected to an air pump, the other end of the aeration tube being
disposed inside the holding tank as close to the bottom of the
holding tank as possible; said supply of air being substantially
continuously supplied via an air supply tube connected to an air
pump, wherein: measurement of air pressure in said aeration tube,
using said pressure sensor, is used to determine liquid level in
said holding tank.
2. The sensor according to claim 1, wherein said pressure sensor
and aeration tube are sealingly connected to one another.
3. The sensor according to claim 1, wherein the substantially
continuous supply of air into said aeration tube in said holding
tank provides air to said sewage to create an oxygen-enriched
environment in said sewage, thereby assisting in reducing the odors
emanating from said sewage within said holding tank.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally pertains to marine and
recreational vehicle (RV) waste holding tanks and, more
particularly, combining in a single apparatus level sensing and
odor reduction for such waste holding tanks.
[0003] 2. Description of Related Art
[0004] Waste from toilets aboard marine vessels and recreational
vehicles is generally flushed by the toilet system into a holding
tank where it is held for treatment, or for disposal into a
land-based sewage handling system. For safety reasons, the holding
tank is always vented to atmosphere. As a result, each time
additional sewage is flushed into the holding tank, air within the
holding tank is displaced by incoming sewage, forcing foul-smelling
air out the vent. The holding tanks are also typically outfitted
with a device for sensing the level of waste in the tank, to
prevent overflow or back-up of sewage.
[0005] Traditionally, the devices for reduction of odor and for
sensing level are embodied in seperate physical mechanisms. For
example, U.S. patent application No.20030080055 employs a supply of
air into the sewage in the holding tank to create an
oxygen-enriched environment in the sewage, thereby assisting in
reducing the odors emanating from the sewage within the holding
tank.
[0006] Physical space is often limited in holding tanks, and having
two devices which must be installed and maintained in the holding
tank increases cost and can reduce reliability.
[0007] Therefore, there exists a need in the art for a device that
can perform both functions of odor-reduction and level sensing in a
single physical embodiment.
SUMMARY OF THE INVENTION
[0008] The present invention is directed toward a device for
sensing the level of sewage in a marine or RV waste holding tank,
while simultaneously and in the same physical package reducing or
eliminating the odors emitted from the holding tank.
[0009] In accordance with the present invention, a marine vessel or
RV includes a waste holding tank, an aeration pump, an aeration
tube, and a pressure sensor. The waste holding tank is installed
within the marine vessel or RV and has the aeration tube disposed
in the tank, as close to the tank bottom as possible. The output of
the aeration pump and aeration tube is in fluid communication with
the sewage in the holding tank, and in fluid communication with the
pressure sensor, and is adapted for operation such that air is
communicated to the aeration tube and the pressure sensor.
[0010] In further accordance with the present invention, the waste
holding tank also includes an inlet for sewage, an outlet through
which sewage is pumped out of the holding tank, and a vent. The
vent is continuously opened, to expel air from the tank.
[0011] In further accordance with the present invention, a method
for sensing the level of sewage in the holding tank is provided.
The method includes:
[0012] a. installation of a pressure sensor at a point on the
aeration tube; and,
[0013] b. supplying power to the pressure sensor for the purpose of
providing an output signal correlated to holding tank sewage
level.
[0014] In further accordance with the present invention, a method
for reducing perceived odors emanating from a marine vessel or RV
waste holding tank is provided. The method includes the steps
of:
[0015] a. submerging an aeration tube in sewage substantially
continuously;
[0016] b. supplying pressurized air to the aeration tube
substantially continuously to thereby inject air into the sewage
surrounding the aeration tube and to create an oxygen-enriched
condition in the sewage; and,
[0017] c. gradually and continuously expelling air from the holding
tank through the vent.
BRIEF DESCRIPTION OF THE DRAWING
[0018] These and further features of the invention will be apparent
with reference to the following description and drawing,
wherein:
[0019] the drawing is a schematic illustration of the
odor-reduction and level-sensing device according to the present
invention.
[0020] In the illustrated embodiment, the pressure sensor 4 is
arranged to one side of the aeration tube 5, with the air supply
line 3 entering the top of aeration tube 5. It is considered
apparent that the positions of the pressure sensor 4 and the air
supply line 3 could be switched or otherwise arranged without
changing the function of the sensor 1 or the system incorporating
the sensor 1. Moreover, the pressure sensor 4 and the air supply
line 3 can be of any shape or orientation. Moreover the aeration
tube 5 can be of any shape.
[0021] The sensor 1 is comprised of the aeration tube 5 which is in
fluid communication with the sewage in the holding tank 6, the
pressure sensor 4 and the air supply line 3. The air supply line 3
is likewise in fluid communication with the air pump 2.
[0022] The sensor 1 of the present invention has one end open as
close to the bottom of the holding tank 6 as possible. The
operation of the air pump 2 supplies air via the air supply line 3.
This causes air to flow through the aeration tube 5into the sewage
in the holding tank 6. The amount of back pressure generated in the
aeration tube 5 will correlate to the level of sewage in the
holding tank 6. The pressure sensor 4 will measure this back
pressure and will provide an output signal that correlates to the
level of sewage in the holding tank 6.
[0023] Although various means of air-tight mechanical attachment
may be employed, the sensor 1 preferably has a hose barb or nipple
compatible with the air supply line 3 in use. In any event, the
sensor 1 will sealingly engage the air line used to connect to air
supply line 3.
[0024] Although various means of air-tight mechanical attachment
may be employed, the sensor 1 will install sealingly in the holding
tank 6.
[0025] The present invention has been described herein with
particularity, but it is noted that the scope of the invention is
not limited thereto. Rather, the present invention is considered to
be possible of numerous modifications, alterations, and
combinations of parts and, therefore, is only defined by the claims
appended hereto.
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